Anatomy of the long bone (1/2)

Human skeletal system consists of bones, Figure 1. Bone
is partly organic (cells and matrix) and partly inorganic (mineralised
component). There are four types of bones: long, short, flat and
irregular. Long bones, especially the femur and tibia, are subjected
to most of the load during daily activities and they are crucial
for skeletal mobility.

Figure 1. Skeleton and long bone definitions.

Long bones have four main functions. The first function is
structural. Bones provide the shape for our bodies and host vital
organs. Body locomotion is the second function of the bone. The
complicated kinematic skeletal system enables movement, using muscles
that control bone positions and orientations. Bones transmit
loads and act as levers. Joints are the fulcrums about which
bones move. Therefore, the prime qualities of bones are strength
and rigidity [1]. Once the
load exceeds the capacity of the bone, the fracture occurs. The
body then initiates bone repair and the reconstruction process in
order to restore bone functional properties. Details of the healing
types and stages are described in the next section of this website.
The third function of the bone is blood cell formation. Blood cell
precursor cells, hemocytoblasts, are found in red marrow. The red
marrow is simply a loose connective tissue that contains these
blood cell precursors and the cells that they are making. The
fourth function of the bone is inorganic salt regulation and
storage of calcium, phosphate, sodium and...
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